1. Field of the Invention
The present invention relates to an apparatus for correcting the vibrations of images due to the vibrations of hands in a video camera, in which the refractive index of a medium is controlled by an electro-optical effect to correct the position of light rays so as to move the images of a zoom lens up and down and to left and right, so that the vibrations of images can be corrected.
2. Description of the Related Art
Detecting moving vectors from signals of an oscillating image is an indispensable technique for picture compression, picture recognition, picture stability, etc.
Photographing with a portable VCR (video cassette recorder) while walking or moving, or with a video camera attached to a moving vehicle, can cause unstable and vibrating images to be generated.
Further, because of miniaturization and greater availability of video cameras, portable video cameras are widely used. However, when photographing with a high ratio lens, instability of images due to vibration from the operator's hands becomes a serious problem.
Video cameras which are currently used have various devices which correct for vibration from the operator's hands. Specifically, in conventional devices, if oscillations of the camera body are detected, recording occurs in a small area instead of over the entire area. In correcting devices of this nature, the input picture is delayed by one field, and the field memory is controlled, or the area to be input is controlled by using a CCD (charge coupled device).
Thus, conventional correcting devices require a CCD or a memory which is larger than the image being filmed, for use as a redundancy area, to prevent picture degradation. Therefore, the bulk of the apparatus becomes large, and the apparatus becomes complicated.
In an attempt to overcome these problems, SONY (Japan) developed a correcting device which directly controls the optical axis of incident light rays with an optical device. One example of this device is shown in FIG. 1, which is a conceptional view showing the principle of this correcting device using an active prism.
Operation of this device will now be explained. First, motion is detected with a gyro sensor, and dislocations of input oscillating images are corrected by using an active prism. The active prism 11 contains fluid 12, so that when incident rays pass through the fluid 12, they are refracted a correct amount before reaching the main CCD 13.
However, in this device, the position and direction of the prism is mechanically controlled, and therefore, there is a limit in the prism driving speed for correcting the vibration of hands and in the controlled resolving power at a high ratio.